[PATCH] D126099: [SLP] Fix crash in reorderBottomToTop().

[Alexey Bataev via Phabricator via llvm-commits]

ABataev added a comment.

Hi Vasileos, thanks for the reproducer and the patch. Could you try something like this instead:

  diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  index a8de0bffe8d5..d74153c4c636 100644
  --- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  +++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
  @@ -3858,7 +3858,7 @@ void BoUpSLP::reorderBottomToTop(bool IgnoreReorder) {
     while (!OrderedEntries.empty()) {
       // 1. Filter out only reordered nodes.
       // 2. If the entry has multiple uses - skip it and jump to the next node.
  -    MapVector<TreeEntry *, SmallVector<std::pair<unsigned, TreeEntry *>>> Users;
  +    DenseMap<TreeEntry *, SmallVector<std::pair<unsigned, TreeEntry *>>> Users;
       SmallVector<TreeEntry *> Filtered;
       for (TreeEntry *TE : OrderedEntries) {
         if (!(TE->State == TreeEntry::Vectorize ||
  @@ -3886,7 +3886,13 @@ void BoUpSLP::reorderBottomToTop(bool IgnoreReorder) {
       // Erase filtered entries.
       for_each(Filtered,
                [&OrderedEntries](TreeEntry *TE) { OrderedEntries.remove(TE); });
  -    for (auto &Data : Users) {
  +    SmallVector<
  +        std::pair<TreeEntry *, SmallVector<std::pair<unsigned, TreeEntry *>>>>
  +        UsersVec(Users.begin(), Users.end());
  +    sort(UsersVec, [](const auto &Data1, const auto &Data2) {
  +      return Data1.first->Idx > Data2.first->Idx;
  +    });
  +    for (auto &Data : UsersVec) {
         // Check that operands are used only in the User node.
         SmallVector<TreeEntry *> GatherOps;
         if (!canReorderOperands(Data.first, Data.second, NonVectorized,

It just simply reorders the users to start the reordering from the bottom elements of the graph rather than from the top.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D126099/new/

https://reviews.llvm.org/D126099